Download-hearts-of-iron-4-field-marshal-edition-v1-9-1-online -

The Field Marshal Edition features are tied to your account's DLC list. Ensure the launcher shows version 1.9.1.

Are you trying to run a specific that only works on version 1.9.1? The Field Marshal Edition features are tied to

If you’ve played newer versions, go to Documents/Paradox Interactive/Hearts of Iron IV and delete the shadercache folder to prevent crashes. The Field Marshal Edition features are tied to

This sounds like you are looking for a specific, older version of the (v1.9.1) to play online. The Field Marshal Edition features are tied to

Steam will automatically download a small update to revert your game files to that 2020 version. Step 3: Enabling Online Play